Medford RWRF Prelim Geotech Memo (12-6-24).pdf

Foundation Engineering, Inc.

Professional Geotechnical Services Memorandum

820 NW Cornell Avenue • Corvallis, Oregon 97330 • 541-757-7645 7857 SW Cirrus Drive, Bldg 24 • Beaverton, Oregon 97008 • 503-643-1541

Date: December 6, 2024

To: Walt Meyer, P.E.

West Yost Associates

From: Matthew Mason, P.E., G.E.

Dave Running, P.E., G.E.

Subject: Preliminary Geotechnical Memorandum

Project: Medford RWRF Improvements Project No.: 2241113

We have completed the exploratory drilling, test pits, ReMi seismic study, and the field and laboratory testing for the Medford RWRF Improvements project in Jackson County, Oregon. This memorandum provides a description of our work to date, a summary of the site conditions, and a preliminary discussion of geotechnical considerations for the project. We have also included a list of requested information from the design team. We will continue with our design and report preparation after we receive feedback on the questions.

There are numerous values in geotechnical investigations that are approximate, including calculated values, measured lengths, soil layer depths and elevations, and strength measurements. For brevity, the symbol “±” is used throughout this memorandum to represent the words approximate or approximately when discussing approximate values.

BACKGROUND

The City of Medford is planning multiple improvements at its Regional Water Reclamation Facility (RWRF). The project location is shown in Figure 1A (Appendix A). Figure 2A shows the layout of the existing facility and the proposed improvements. The improvements that require geotechnical input include construction of four (4) clarifiers, a bardenpho complex, a denitrification filter, a plant drain pump station, a junction box, a filter pump station, a blower building, a maintenance building, an administration building, a new drying bed, and a new storm drain transmission line located south of the RWRF adjacent to Kirtland Road. New asphalt concrete pavement (ACP) is also planned within the facility.

The City of Medford is the project owner and West Yost Associates (West Yost) is the prime designer. Foundation Engineering was retained by West Yost to complete a geotechnical investigation and a site-specific seismic hazard study (SHS) for the project. Our scope of work was outlined in a proposal dated August 20, 2024, and was authorized by Task Order No. 31 dated August 30, 2024.

Medford RWRF Improvements December 6, 2024 Preliminary Geotechnical Memorandum 2. Project No.: 2241113 Jacson County, Oregon West Yost Associates

FIELD EXPLORATION

Borings

We drilled 15 exploratory borings (BH-1 through BH-15) at the site between September 17 and 29, 2024. The boring locations were selected to coincide with proposed structures. The approximate boring locations are shown in Figure 2A.

The borings were drilled by Crisman Pacific Strata Drilling, LLC. using a CME850 track-mounted drill rig and mud-rotary drilling methods. Drilling extended to depths of ±15 to 50 feet. Soil samples were typically obtained at 2½-foot intervals to a depth of 10 feet and at 5-foot intervals thereafter. Sampling was conducted using a split-spoon sampler in conjunction with the Standard Penetration Test (SPT). The SPT, which is performed when the split-spoon sampler is driven, provides an indication of the stiffness or density of the foundation soil. The sampler is driven three consecutive 6-inch increments, and the blows required to drive the sampler through each increment are recorded. The number of blows required to drive the sampler the final 12 inches represents the standard penetration resistance or N-value in blows per foot (bpf). SPT refusal is defined by a penetration resistance exceeding 50 blows in a 6-inch increment.

Upon completion of drilling, 2-inch (I.D.) standpipe piezometers were installed in BH-2 and BH-11 to allow monitoring of the groundwater levels throughout the design phase. The other boreholes were backfilled with bentonite chips in accordance with Oregon Water Resources Department (OWRD) guidelines. The backfill was capped with crushed rock and asphalt concrete pavement (ACP) cold patch where borings were drilled in paved areas.

Test Pits

We dug 8 test pits (TP-1 through TP-8) at the proposed drying bed location on November 5, 2024. The approximate test pit locations are shown in Figure 2A. The explorations were completed using a Kubota KX040-4 track-mounted excavator. The excavations extended to depths of ±5 to 9 feet. The subsurface conditions were documented, and grab samples of the soil were taken at selected depths. Upon completion of the exploration the test pits were backfilled with the excavated materials and the ground surface was graded relatively smooth.

The borings and test pits were logged by an FE representative. Draft exploration logs were prepared based on a review of the field logs, the laboratory test results, and an examination of the soil and rock samples in our office. The logs are provided in Appendix B. Ground surface elevations shown on the logs were estimated from a topographic site plan prepared by Pariani Land Surveying. Important Information and Symbols and the Common Soil and Rock Descriptions Terms sheets are included in Appendix B that provide additional information regarding the exploration logs and the definitions of symbols and descriptive terms used in the logs. The sheets also include a discussion of the interpretation of the subsurface profile at the exploration locations and the potential for inherent variations in the subsurface conditions across the site.

Preliminary Geotechnical Memorandum 3. Project No.: 2241113 Jacson County, Oregon West Yost Associates

SUBSURFACE CONDITIONS

Our explorations indicate the upper ±5 to 10 feet of the subsurface profile is variable and includes fill (at some locations) and alluvium. The upper alluvium includes clayey gravel, sandy clay and clayey sand with variable amounts of gravel and cobbles, silt, sandy silt, silty sand, and gravel with variable amounts of silt, clay, sand, and cobbles. The fine-grained soil was typically stiff to very stiff and the coarse-grained soil was medium dense to very dense. A ±1 to 2.5-foot thick layer of cemented silt was encountered in the test pits typically between depths of ±2 to 4.5 feet. We anticipate the cemented layer is present across the site. However, a cemented layer was not identified in the borings due to limited sample recovery and sample disturbance during SPT sampling.

The upper alluvium is underlain by predominantly coarse-grained alluvium (referred to herein as the lower alluvium). The lower alluvium consists of very dense gravel with varying amounts of silt, clay, sand, and cobbles. Most of the borings terminated in this stratum at depths ranging from ±15 to 35 feet.

The deeper borings encountered bedrock of the Payne Cliffs Formation below the lower alluvium at depths of ±42 feet (±El. 1162.5) in BH-2, ±44.5 feet (±El. 1160.5) in BH-4, and ±47.0 feet (±El. 1159.5) in BH-11. The bedrock includes slightly weathered to fresh, very weak to weak (R1 to R2) mudstone, sandstone, and silty sandstone.

We used the topographic survey information and the subsurface information from several of the borings to develop a Cross-Section A-A’ extending through the bardenpho complex and the center of the planned 115-foot diameter clarifiers. The Cross-Section A-A’ location is shown in Figure 2A, and the surface profile and interpreted subsurface conditions are shown in Figure 3A. For the cross-section, the subsurface profile was divided into an upper alluvium stratum, a lower alluvium stratum, and a bedrock stratum as described above. The cross-section indicates relatively uniform subsurface conditions across the site where the deepest excavations are planned (i.e., bardenpho complex and clarifiers). The bedrock surface underlying these structures is relatively flat and the bedrock elevations range from ±El. 1159.5 near the south end of the bardenpho to ±El. 1162.5 at the center of the northern most clarifier.

GROUNDWATER

No groundwater was encountered in the test pits, which extended to depths of ±5 to 9 feet. The use of mud-rotary drilling methods precluded the measurement of groundwater levels in the borings at the time of drilling. Following drilling at BH-9 and BH-15, the boreholes were bailed and left open to allow the water level to recharge. Groundwater depths were measured at these locations ±1 to 3 days following drilling. The recorded groundwater levels are noted in the boring logs and in Table 1.

Preliminary Geotechnical Memorandum 4. Project No.: 2241113 Jacson County, Oregon West Yost Associates

The piezometers in BH-2 and BH-11 were bailed and allowed to recharge to confirm the initial groundwater depths. The baseline readings were taken on September 29, 2024. We returned to the site on October 24, 2014, and took additional readings.

We also installed HOBO water level data loggers in the piezometers to allow for automated measurements of the groundwater levels. The data loggers were set to record groundwater levels at 12-hour intervals.

The manual groundwater measurements recorded to date are summarized in Table 1.

We will provide the HOBO water level data in the future.

Table 1. Groundwater Summary to Date

Boring Date Groundwater Depth (ft)

Groundwater Elevation (ft)

BH-2

9/29/24 18.2 1186.3

10/24/24 14.2 1190.3

BH-9 9/29/24 7.5 1196.5

BH-11

9/29/24 9.4 1197.1

10/24/24 9.0 1197.5

BH-15 9/27/24 6.5 1221.5

Notes:

1. Groundwater depths at BH-2 and BH-11 reference the tops of the monuments, which are flush with the ground surface.

2. Groundwater depths in BH-9 and BH-15 reference the ground surface.

The groundwater levels reported in Table 1 are consistent with historical groundwater levels recorded at the Clarifier #5 monitoring well between May and November 2016 (data provided by West Yost). The historical monitoring data indicated the groundwater level ranges from ±10.25 to 20.45 feet below the surface of the concrete vault. These depths correspond to ±El. 1191.8 to ±El. 1181.6 (elevations reference an onsite vertical datum establish by RWRF personnel).

The estimated groundwater surface at the time of our field investigation is shown in Figure 3A. The groundwater levels were estimated based on groundwater readings in BH-2, BH-9, and BH-11 on September 29, 2024. The available data indicates groundwater surface dips to the north across the facility and drains towards the Rogue River, which is located along the northern limits of the site. The Rogue River is incised ±40 to 45 feet below the RWRF site and the bottom of the river channel is likely at or close to the bedrock surface. We anticipate the groundwater levels will fluctuate seasonally with the highest levels occurring during the winter and spring.

The highest seasonal fluctuations may occur at the north end of the site following fluctuations in the river level.

Preliminary Geotechnical Memorandum 5. Project No.: 2241113 Jacson County, Oregon West Yost Associates

We anticipate a perched water condition will also occur near the ground surface during periods of sustained, wet weather due to the low permeability of the shallow fine-grained soil and the presence of a cemented soil layer. The perched water typically disappears in the summer.

FIELD AND LABORATORY TESTING

Laboratory Testing

The laboratory testing included moisture contents, percent fines, and Atterberg limits tests to help classify the soils and estimate their overall engineering properties. The results of these tests are summarized in Table 1C (Appendix C). Non tested samples were visually classified in accordance with ASTM D2488-09a, ASTM D 2487-11, and the Unified Soil Classification System to estimate their overall engineering properties.

Resistivity and pH Testing

In-situ resistivity testing was completed using a Miller 400A 4-pin soil resistance meter (ASTM G57). The resistivity test was completed in the vacant parcel located ±60 feet east of Clarifier #5 (i.e., in the vicinity of the planned clarifiers). The test location is shown in Figure 2A. The 4-pin resistance meter provides an estimate of the average resistivity of a soil profile extending to a depth equal to the spacing between the pins. The resistivity tests were performed with the pins spaced at ±5, 10, 15, and 20 feet. The test results, summarized in Table 2C, indicate resistivity values ranging from 7,181 to 17,235 ohm-cm. These values are within the typical ranges for the soil encountered at the site.

pH tests (ASTM G51) were completed on sandy clay or silty sand samples obtained in BH-2 and BH-4 in the upper ±30 feet of the subsurface profile. The results, summarized in Table 3C, indicate pH values ranging from 6.3 to 7.8 and correspond to slightly acidic to slightly alkaline soil conditions. The pH and resistivity test results suggest relatively low potential for corrosion of buried steel.

ReMi Shear Wave Velocity Testing

A shear wave velocity (Vs) profile for the site was developed to a depth of ±100 feet using the refraction microtremor (ReMi) method. ReMi testing is performed at the ground surface by setting up a linear array of geophones and recording ambient seismic “noise”. The testing was completed by Earth Dynamics, LLC on November 5, 2024, to assist in characterization of the soil profile for seismic design.

The approximate location of the ReMi geophone array is shown in Figure 2A. The results of the testing are summarized in Earth Dynamic’s report which is presented in Appendix D and discussed in more detail below.

Preliminary Geotechnical Memorandum 6. Project No.: 2241113 Jacson County, Oregon West Yost Associates

GEOTECHNICAL DESIGN CONSIDERATIONS

The following provides a preliminary discussion of geotechnical design considerations for the project. We will provide additional design recommendation in a geotechnical report after the design of the facility progresses.

Seismic Design

Liquefaction Hazard. Liquefiable soils typically consist of saturated, loose sand and silty sand and non-plastic or low plasticity silt (i.e., PI less than 8). Our explorations indicate the site is underlain by predominantly dense to very dense coarse-grained alluvium to ±42 to 47 feet followed by bedrock. These materials are not susceptible to liquefaction. Therefore, there are no liquefaction, lateral spread, or seismically-induced settlement hazards at the site.

Design Response Spectrum. At the request of the design team, a Design Response Spectrum was developed for the project in accordance with ASCE 7-22. It is anticipated that the design criteria outlined in ASCE 7-22 will be followed in the proposed 2025 Oregon Structural Specialty Code (OSSC). The current 2022 OSSC is based on ASCE 7-16 criteria. Changes between the standards that affect seismic design include the following:

• The ASCE 7-22 design response spectrum prescribed in Chapter 11 consists of a multi-period response spectrum (MPRS) that defines risk-targeted maximum considered earthquake (MCER) ground motions at 22 response periods. This approach is intended to “improve the accuracy of the frequency content of earthquake design ground motions and enhance the reliability of the seismic design parameters derived from these ground motions” compared with the two-period response spectrum used in ASCE 7-16. ASCE 7-22 still includes a two period design response spectrum to be used where multi-period data is not available.

• The ASCE 7-22 MCER ground motions are based on the 2018 update of the USGS National Seismic Hazard Model (NSHM) for the conterminous United States. The ASCE 7-16 MCER ground motions are based on the 2014 update of the USGS NSHM.

• The MCER ground motions obtained from the modified 2018 USGS maps are based on a 2% probability of exceedance in 50 years (i.e., 2,475-year return period) and directly incorporate site amplification and other site effects in the design parameters SDS and SD1 (two-thirds of SMS and SM1) and thereby eliminate the need for site class coefficients (Fa and Fv) that were used in the development of the ASCE 7-16 site response spectra.

• The number of site classifications has increased from five in ASCE 7-16 to eight in ASCE 7-22 to better model the accuracy of site amplification effects on the design parameters.

Preliminary Geotechnical Memorandum 7. Project No.: 2241113 Jacson County, Oregon West Yost Associates

The MCER ground motions were directly obtained from the USGS Seismic Design geodatabase accessed using the ASCE 7 online hazard tool. The Site Class used in calculating ground motion parameters is based on definitions provided in Chapter 20 of ASCE 7-22, where the subsurface is characterized based on the stiffness/density of the soil or the average shear wave velocity within the upper 100 feet of the soil profile (Vs30). The ReMi testing by Earth Dynamics, LLC indicates a Vs30 of 3,061 ft/s.

This shear wave velocity is near the boundary between a Site Class B (medium hard rock) and a Site Class BC (soft rock). To account for statistical uncertainty in the calculations, we recommend assuming a Site Class BC for design. The seismic design parameters and the ASCE 7-22 multi-period Design Response Spectrum are shown in Figure 4A. For comparison, Figure 4A also shows the two-period response spectrum.

Foundation Design

The site is underlain by predominantly stiff or dense alluvium at shallow depths followed by very dense gravel and cobbles. Based on these conditions, we conclude that conventional shallow foundations are suitable to support the at-grade structures, and a conventional mat foundation is suitable to support the below-grade structures.

Bearing capacity and foundation settlement are not expected to be design concerns.

For preliminary design, we recommend designing the at-grade footings for static loading using an allowable bearing pressure of 2,500 psf. This value can be assumed to be a net allowable bearing pressure (i.e., the weight of the footing and the overlying backfill may be ignored when sizing footings using this allowable bearing pressure). This allowable bearing pressure includes a typical factor of safety (FS) of 3. The allowable bearing pressure may be increased by one-third for transient (seismic and wind) loads.

The allowable bearing pressures for the below-grade structures will vary with depth.

We will provide specific net allowable bearing pressures for the individual below-grade structures once their depths and dimensions are established.

Additional foundation design parameters (i.e., estimated settlement, sliding coefficient, passive resistance, modulus of subgrade reaction, lateral earth pressures) will be provided in our forthcoming geotechnical report.

CONSTRUCTION CONSIDERATIONS

Excavation, Shoring, and Dewatering

Most of the improvements consist of below-grade structures (i.e., plant drain pump station, clarifiers, bardenpho complex, junction box, filter pump station, and the denitrification filter). Based on information provided in the draft preliminary design drawings prepared by West Yost, we anticipate excavations extending ±15 to 33 feet below current grades will be required for these structures. The subsurface conditions encountered in our borings indicate the excavations will encounter predominantly very dense gravel with varying amounts of silt, clay, and cobbles.

Preliminary Geotechnical Memorandum 8. Project No.: 2241113 Jacson County, Oregon West Yost Associates

Observations of the drilling action during exploration suggest boulders may also be encountered in the alluvial gravel. Therefore, it should be anticipated that the excavation may encounter boulders of varying sizes.

Depending on the structure location and time of year, groundwater may be encountered within ±7.5 to 25 feet of the ground surface. Therefore, construction dewatering should be anticipated at most locations. Dewatering may include well points or dewatering wells outside the excavation, sumps inside the excavation, or a combination of these options. The contractor will be responsible for designing, installing, and maintaining the dewatering system.

The coarse-grained soils correspond to an OR-OSHA Type C soil. For this material, OR-OSHA recommends a maximum allowable cut slope of 1½(H):1(V) for open excavations less than 20 feet deep. The gravelly soils are susceptible to caving when subjected to sustained groundwater seepage. Therefore, the temporary slopes may have to be flattened or benched due to groundwater seepage. We anticipate open excavation will only be practical for structures located in the northern portion of the site where groundwater is expected to be lower, for excavations less than 20 feet deep, and for work completed during the dry summer months.

We anticipate shoring will be required for the deeper structures in the central portion of the facility and for new structures that are adjacent to existing structures.

Therefore, it should be assumed shoring will be needed for the clarifiers, the bardenpho complex, the junction box, and the filter pump station.

We anticipate the use of a driven sheet pile wall system is not viable due to the presence of very dense gravel and cobbles and the possible presence of boulders, which will make sheet pile driving impractical. We anticipate the most practical shoring option for excavations less than 20 feet will be a soldier pile wall with timber lagging. The advantage of a soldier pile wall system is that the vertical elements can be predrilled to facilitate placement into the very dense gravel stratum. Once the soldier piles are installed, timber lagging can be placed between the piles to retain the soil as the excavation advances. Tie-back anchors should be anticipated for excavation depths greater than 15 feet. The number of tie-back anchors will depend on the final excavation depth, the pile sizes and spacings, the anchor capacities, and potential conflicts with existing below-grade structures. Multiple rows of tie-back anchors may be required for deeper excavations.

The use of a soldier pile wall system is only viable if an adequate groundwater dewatering system can be implemented. We anticipate an extensive dewatering program will be required given the sizes and depths of some of the improvements (i.e., the bardenpho complex), the presence of shallow groundwater, and the presence of highly permeable gravel and cobbles. The use of a soldier pile wall system will also be problematic for the deeper excavations along the west side of the bardenpho complex that will be within ±30 feet of the existing aeration basin and for portions clarifier excavations that are adjacent to the existing clarifiers. The use of tie-back anchors would not be feasible in those areas. Given these considerations, Preliminary Geotechnical Memorandum 9. Project No.: 2241113 Jacson County, Oregon West Yost Associates we anticipate an alternative shoring system will be required for a portion or the entire excavation for the bardenpho complex and the clarifiers.

A secant wall may be a possible option for the areas requiring deep excavations and/or adjacent to existing structures. A secant wall system consists of installing a row of intersecting drilled piers. The primary drilled piers are installed first with spacing in between. The secondary piers are then installed between the primary piers slightly intersecting those piers to create a continuous wall. The primary piers are reinforced with steel. The secondary piers may or may not be reinforced depending on the loading conditions. A properly sized secant wall system may eliminate the need for tie-back anchors. However, internal bracing with walers, rakers and struts may be required. If the secant wall system extends around the entire individual excavation and extends through the alluvial gravel and into the underlying bedrock, the shoring system will act as a cut-off wall to significantly reduce the dewatering requirements.

We assume the contractor will select the shoring system to fit their proposed construction approach and existing site conditions. The shoring system should be designed by a licensed engineer. To help facilitate shoring design, our report will include recommended lateral earth parameters for the subsurface profile anticipated at the site.

Groundwater Drawdown Effects

Excavation dewatering is expected to drawdown the water table in the vicinity of nearby structures (i.e., the existing clarifiers, the aeration basin, and the blower building). A drawdown in the water table increases the effective stress in the foundation soil. In some cases, the increase in effective stress can cause settlement of structures. However, for this project we do not expect significant settlement of existing structures due to groundwater drawdown because the existing structures are underlain by predominantly very dense coarse-grained soils. In addition, we anticipate a similar drawdown was previously required for construction of those structures. Therefore, the risk of settlement from a properly designed and installed dewatering system is low.

Although we deem the settlement risk low for dewatering, we recommend conducting a preconstruction survey of the adjacent structures and establishing survey benchmarks for the facilities to monitor potential settlement during.

QUESTIONS FOR THE DESGIN TEAM

Additional information will be required for the completion of our work. Below is a list of requested information and questions for the project design team:

• When is construction anticipated to commence and what is the expected duration of the work?

Preliminary Geotechnical Memorandum 10. Project No.: 2241113 Jacson County, Oregon West Yost Associates

• The preliminary drawings indicate finish floor elevations (FFE) for most of the below-grade structures. Please confirm or update the FFEs listed below and provide similar information for the clarifiers and plant drain pump station.

o Junction Box: FFE of El. 1191.0 o Bardenpho Basins: FFE of El. 1178.0 o Filter Pump Station: FFE of El. 1183.3 o Denitrification Filters: FFE of 1195.8 o Clarifiers: FFE of ___? (Please provide the elevation at the base of the wall and at the deepest point of the clarifier.)

o Plant drain pump station: FFE of ____?

• Please provide the estimated thickness of the base slab/mat foundation for the following structures so we can estimate the required excavation depths:

o Plant drain pump station o Clarifiers o Bardenpho complex o Junction box o Filter pump station o Denitrification filter

• It appears that most of the below-grade structures will extend below the seasonal high groundwater level. Will a sub-slab drainage system and sump pumps be installed to relieve the potential uplift forces when the structures are drained, or will the base slabs be designed to resist the uplift forces? We will provide design uplift pressure for each structure after we receive confirmation of the bottom of slab elevations.

• Please provide FFEs for the at-grade administration, blower, chemical feed, and the maintenance buildings.

• Please provide a grading plan for the drying bed.

We trust this information meets your present needs and anticipate this memorandum will be forwarded to other members of the design team. Please contact us if you have any questions.

Attachments

Appendix A Figures

Foundation Engineering, Inc.

Professional Geotechnical Services

NVilleneuve Image

4,0002,0001,000

SCALE IN FEET

SITE

Foundation Engineering, Inc.

Professional Geotechnical Services

Nov. 20, 2024

PROJECT NO.

FIGURE NO.

DRAWN BY:DATE:

VICINITY MAP

MEDFORD RWRF IMPROVEMENTS

JACKSON COUNTY, OREGONMDM2241113

1A

Source: USGS (Sams Valley Quadrangle, Oregon), 2024 .ed

BH-3

BH-4

BH-5

BH-1

BH-7

BH-6

BH-8

BH-9

BH-10

BH-11

TP-2

TP-1

TP-6

TP-3

TP-5

TP-4 TP-7

TP-8

BH-13

BH-12

BH-14

BH-15

Clarifier #5

ReMi Array

Resistivity Test Clarifier #6Clarifier #3

Clarifier #2

Clarifier #1

A' A

BH-2

Cross-Section A-A' (see Figure 3A)

Foundation Engineering, Inc.

Professional Geotechnical Services

Dec. 6, 2024

PROJECT NO.

FIGURE NO.

DRAWN BY:DATE:

SITE LAYOUT AND EXPLORATION LOCATIONS

MEDFORD RWRF IMPROVEMENTS

MEDFORD, OREGONMDM2241113

2A Notes:

1. Exploration locations are approximate only.

2. See report for a discussion of site conditions.

3. Base drawing was provided by West Yost Associates.

SCALE IN FEET

0 100 200 400

Legend

- Boring (BH-1)

- Test Pit (TP-1)

El ev at io n (ft

0+00 0+50

A

1+00 1+50 2+00 2+50 3+00 3+50 4+00 4+50 5+00 5+50

BH-11

(El. 1206.5)

50.3'

Depth

BH-4

(El. 1205.0)

45.3'

Depth

BH-9

(El. 1204.0)

BH-10

(El. 1205.0)

BH-8

(El. 1204.0)

36.4'35.7' 35.3'

LOWER ALLUVIUM

UPPER ALLUVIUM

BEDROCK

LOWER ALLUVIUM

UPPER ALLUVIUM

BEDROCK

?47' (El. 1159.5) 44.5' (El. 1160.5)

7' (El. 1199.5) 7.5' (El. 1196.5) 9' (El. 1196.0) 6.5' (El. 1198.5)

Existing Ground Surface

Existing Wetlands

9.4' (El. 1197.1) 9/29/24 7.5' (El. 1196.5)

9/29/24

4.5' (El. 1199.5)

Proposed Bardenpho Complex Proposed Clarifiers

6+00 6+50 7+00 7+50 8+00 8+50 9+00 9+50 10+00 10+50

BH-2

(El. 1204.5)

50.1'

Depth

El ev at io n (ft

A'

BH-5

(El. 1204.5)

25.2'

BH-3

(El. 1205.0)

35.3'

LOWER ALLUVIUM

UPPER ALLUVIUM

BEDROCK

LOWER ALLUVIUM

UPPER ALLUVIUM

BEDROCK

42' (El. 1162.5)

5' (El. 1200.0) 8.3' (El. 1196.2) 7.5' (El. 1197.0)

Rogue River?

Existing Ground Surface

18.2' (El. 1186.3) 9/29/24

Proposed Clarifiers Proposed Plant Drain Pump Station

Foundation Engineering, Inc.

Professional Geotechnical Services

Dec. 6, 2024

PROJECT NO.

FIGURE NO.

DRAWN BY:DATE:

CROSS-SECTION A-A'

MEDFORD RWRF IMPROVEMENTS

MEDFORD, OREGONMDM2241113

3A

SCALE IN FEET

0 20 40 80

Notes:

1. Surface cross-section based on topographic data prepared by Pariani Land Surveying.

2. Subsurface profile interpolated based on conditions encountered in BH-2 through BH-5 and BH-8 through BH-11.

3. Groundwater level estimated based on water levels recorded in BH-2, BH-9, and BH-11 on 9/29/24. Groundwater levels are expected to vary seasonally.

4. See report for a discussion of site conditions.

M at ch lin e 5+

M at ch lin e 5+

Unit Descriptions Upper Alluvium: Includes clayey gravel, sandy clay, and clayey sand with variable amounts of gravel and cobbles, silt, sandy silt, silty sand, and gravel with variable amounts of silt, clay, sand, and cobbles. The fine-grained soil is typically stiff to very stiff and the coarse-grained soil is medium dense to very dense.

Lower Alluvium: Consists of predominantly very dense gravel with varying amounts of silt, clay, sand, and cobbles.

Bedrock: Includes slightly weathered, very weak to weak (R1 to R2) mudstone, sandstone, and silty sandstone (Payne Cliffs Formation)

S N

Notes:

1. The Design Response Spectrum is based on ASCE 7-22 Section 11.4.5.

2. The following parameters were obtained from the USGS Seismic Design Geodatabase accessed using the online ASCE 7-22 Hazard Tool:

Site Class= BC Damping = 5%

SS = 0.74 SMS = 0.67 SDS = 0.44

S1 = 0.34 SM1 = 0.36 SD1 = 0.24

3. SS and S1 values indicated in Note 2 are the mapped, risk-targeted maximum considered earthquake spectral acclerations for 2% probability of exceedence in 50 years.

4. SMS and SM1 values indicated in Note 2 are the mapped, risk-targeted maximum considered earthquake spectral acclerations for 2% probability of exceedence in 50 years and adjusted for site class effects. SDS and SD1 values include a 2/3 reduction on SMS and SM1 as discussed in ASCE 7-22 Section 11.4.4.

5. Site location is: Latitude 42.4358, Longitude -122.9035.

Jackson County, Oregon

Figure 4A

Medford RWRF Improvements ASCE 7-22 Design Response Spectrum

Project No.: 2241113

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.5 1 1.5 2 2.5 3

Sp ec tr al

A cc el er at io n, S a (g

Period (seconds)

ASCE 7-22 Multi-Period Design Response Spectrum

ASCE 7-22 Two-Period Design Response Spectrum

Appendix B Boring and Test Pit Logs

Foundation Engineering, Inc.

Professional Geotechnical Services

Professional Geotechnical Services IMPORTANT INFORMATION AND SYMBOLS

EXPLORATION LOG KEY

DISTINCTION BETWEEN FIELD LOGS AND FINAL LOGS

A field log is prepared for each exploration by our field representative. The log contains information concerning sampling depths and the presence of various materials such as gravel, cobbles, and fill, and observations of groundwater. It also contains our interpretation of the soil conditions between samples. The final logs presented in this report represent our interpretation of the contents of the field logs and the results of the sample examinations and laboratory test results. Our recommendations are based on the contents of the final logs and the information contained therein and not on the field logs.

VARIATION IN SOILS BETWEEN EXPLORATIONS

The final log and related information depict subsurface conditions only at the specific location and on the date indicated. Those using the information contained herein should be aware that soil conditions at other locations or on other dates may differ. Actual foundation or subgrade conditions should be confirmed by Foundation Engineering during construction.

TRANSITION BETWEEN SOIL OR ROCK TYPES

The lines designating the interface between soil, fill, or rock on the final logs and on subsurface profiles presented in the report are determined by interpolation and are therefore approximate. The transition between the materials may be abrupt or gradual. Only at boring or test pit locations should profiles be considered as reasonably accurate and then only to the degree implied by the notes thereon.

SS - 3 - 4

Bottom of Sample Attempt

Unrecovered Portion

Exploration Number

Recovered Portion

Top of Sample Attempt

Sample Type

Sample Number

SAMPLE AND TEST SYMBOLS

- Pavement Core Sample

- Rock Core Sample

- Oversize Sample (3-inch O.D. split-spoon)

- Grab/ Bulk Sample

- Thin-walled Undisturbed Sample

- SPT Sample (2-inch O.D. split-spoon)

- Rotosonic Sample Interval

FIELD SHEAR STRENGTH TEST

Shear strength measurements on test pit side walls, blocks of soil or undisturbed samples are typically made with Torvane (ASTM D8121) or Field Vane (ASTM D2573) shear devices. Values reported as undrained shear strength (Su) in tons per square foot (tsf).

TYPICAL SOIL/ROCK SYMBOLS

GROUNDWATER

Groundwater Depth (ft)

Date of Measurement(1/31/21)

Concrete

Organics

Clay Gravel

Silt

Sand Sandstone

Basalt

Siltstone

Standard Penetration Test resistance equals the number of blows a 140 lb. weight falling 30 in. is required to drive a standard split-spoon sampler 1 ft. Practical refusal is equal to 50 or more blows per 6 in. of sampler penetration.

Water Content (%)

SSSH

C

CS

OS

S

SH

SS

RUN #

CS

or

RUN

UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)

G - Gravel W - Well Graded

S - Sand P - Poorly Graded

M - Silt L - Low Plasticity

C - Clay H - High Plasticity

Pt - Peat O - Organic

Professional Geotechnical Services COMMON SOIL DESCRIPTION TERMS

EXPLORATION LOG KEY

FIELD IDENTIFICATION

COHESIVE SOILS GRANULAR SOILS

SPT* Su** (tsf) TERM SPT* TERM

Easily penetrated several inches by fist. 0 - 2 < 0.125 Very Soft 0 - 4 Very Loose

Easily penetrated several inches by thumb. 2 - 4 0.125 - 0.25 Soft 4 - 10 Loose

Can be penetrated several inches by thumb with moderate effort. 4 - 8 0.25 - 0.50 Medium Stiff 10 - 30 Medium Dense

Readily indented by thumb but penetrated only with great effort. 8 - 15 0.50 - 1.0 Stiff 30 - 50 Dense

Readily indented by thumbnail. 15 - 30 1.0 - 2.0 Very Stiff > 50 Very Dense

Indented with difficulty by thumbnail. > 30 > 2.0 Hard

TERM SOIL MOISTURE FIELD DESCRIPTION

Dry Absence of moisture. Dusty. Dry to the touch.

Damp Soil has moisture. Cohesive soils are below plastic limit and usually moldable.

Moist Grains appear darkened, but no visible water. Silt/clay will clump. Sand will bulk. Soils are often at or near plastic limit.

Wet Visible water on larger grain surfaces. Sand and cohesionless silt exhibit dilatancy. Cohesive soil can be readily remolded. Soil leaves wetness on the hand when squeezed. Soil is wetter than the optimum moisture content and above the plastic limit.

TERM PI PLASTICITY FIELD TEST

Non-plastic 0 - 3 Cannot be rolled into a thread at any moisture.

Low Plasticity 3 - 15 Can be rolled into a thread with some difficulty.

Medium Plasticity 15 - 30 Easily rolled into thread.

High Plasticity > 30 Easily rolled and re-rolled into thread.

TERM SOIL STRUCTURE CRITERIA

Stratified Alternating layers at least ¼ inch thick.

Laminated Alternating layers less than ¼ inch thick.

Fissured Contains shears and partings along planes of weakness.

Slickensided Partings appear glossy or striated.

Blocky Breaks along surfaces into smaller lumps or blocks. Slickensides may be visible.

Lensed Contains pockets of different soils.

TERM SOIL CEMENTATION CRITERIA

Weak Breaks under light finger pressure.

Moderate Breaks under hard finger pressure.

Strong Will not break with finger pressure.

* SPT N-value in blows per foot (bpf) ** Undrained shear strength

Professional Geotechnical Services COMMON ROCK DESCRIPTION TERMS

EXPLORATION LOG KEY

Rock Quality Designation (RQD) is the cumulative length of intact rock core pieces 4 inches or longer (excluding breaks caused by drilling and handling) divided by run length, expressed as a percentage.

Field Identification UCS (psi) Strength Hardness

(ODOT)

Indented by thumbnail. R0 < 100 Extremely Weak Extremely Soft

Crumbles under firm blows with geological hammer.

Can be peeled by a pocket knife. R1 100 - 1,000 Very Weak Very Soft

Can be peeled by a pocket knife with difficulty, shallow indentations made by firm blow with geological hammer. R2 1,000 - 4,000 Weak Soft

Cannot be scraped or peeled with a pocket knife, specimen can be fractured with a single blow of geological hammer. R3 4,000 - 8,000 Medium Strong Medium Hard

Specimen requires more than one blow of geological hammer to fracture it. R4 8,000 - 16,000 Strong Hard

Specimen requires many blows of geological hammer to fracture it. R5 > 16,000 Very Strong Very Hard

Term (ODOT) Weathering Field Identification

Fresh Crystals are bright. Discontinuities may show some minor surface staining. No discoloration in rock fabric.

Slightly Weathered Rock mass is generally fresh. Discontinuities are stained and may contain clay. Some discoloration in rock fabric.

Moderatedly Weathered

Significant portions of rock show discoloration and weathering effects. Crystals are dull and show visible chemical alteration. Discontinuities are stained and may contain secondary mineral deposits.

Highly Weathered (Predominately Decomposed)

Rock can be excavated with geologist's pick. All discontinuities exhibit secondary mineralization. Complete discoloration of rock fabric. Surface of core is friable and usually pitted due to washing out of highly altered minerals by drilling water.

Decomposed Rock mass is completely decomposed. Original rock "fabric" may be evident (relict texture). May be reduced to soil with hand pressure.

Spacing (metric) Spacing (imperial) Spacing Term Bedding/Foliation < 6 cm < 2 in Very Close Very Thin (Laminated)

6 cm - 30 cm 2 in - 1 ft Close Thin 30 cm - 90 cm 1 ft - 3 ft Moderately Close Medium 90 cm - 3.0 m 3 ft - 10 ft Wide Thick

> 3.0 m > 10 ft Very Wide Very Thick (Massive)

Vesicle Term Volume Some vesicles 5 - 25%

Highly vesicular 25 - 50%

Scoriaceous > 50%

Stratification Term Description Lamination < 1 cm (0.4 in) thick beds

Fissile Preferred break along laminations

Parting Preferred break parallel to bedding

Foliation Metamorpic layering and segregation of minerals

RQD % Designation RQD % Designation 0 - 25 Very Poor 75 - 90 Good 25 - 50 Poor 90 - 100 Excellent 50 - 75 Fair

Backfilled with bentonite chips

SS-1-1

SS-1-2

SS-1-3

SS-1-4

SS-1-5

SS-1-6

SS-1-7

SS-1-8

SS-1-9

SOD (±1-inch).

Very dense clayey GRAVEL and COBBLES, trace sand (GC); brown, damp, medium to high plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense sandy GRAVEL and COBBLES, trace silt (GP); grey-brown, moist, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense GRAVEL, some silt and sand, scattered cobbles (GP-GM); grey-brown, wet, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense GRAVEL and COBBLES, some silt and sand (GP-GM); grey-brown, wet, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense clayey GRAVEL, trace sand (GC); grey, wet, high plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium)

BOTTOM OF BORING

1202.9 0.1

1198.0 5.0

1185.5 17.5

1180.0 23.0

1173.5 29.5

1167.6 35.4

SPT

N-Value

Moisture (%) Groundwater Log

Depth

Depth and

Comments

Core Recovery (%)

RQD (%)

0 50 100

Elev. Backfill/ Installations/

(ft)

Sample Number and Location

Soil / Rock Description

2241113

BORING LOG: BH- 1Project No.:

Surface Elevation:

Date of Boring: September 29, 2024

Medford RWRF Improvements

Jackson County, Oregon

BH- 1

1203.0 feet (Approx.)

Professional Geotechnical Services Foundation Engineering, Inc.

50/1st 6"

50/4"

50/1st 6"

50/1st 5"

50/1st 2"

50/1st 5"

50/1st 3"

50/5"

50/1st 5"

50/1st 6"

50/4"

50/1st 6"

50/1st 5"

50/1st 2"

50/1st 5"

50/1st 3"

50/5"

50/1st 5"

Morris monument set in PCC

2-inch I.D.

PVC

Bentonite chips

Groundwater (9/29/24)

Silica Sand

Machine slot screen

(No. 0.010)

Bentonite chips

Gravel

SS-2-1

SS-2-2

SS-2-3

SS-2-4

SS-2-5

SS-2-6

SS-2-7

SS-2-8

SS-2-9

SS-2-10

SS-2-11

SS-2-12

SS-2-13

SOD (±2 inches).

Dense silty GRAVEL and COBBLES, some sand (GM);

brown, dry, low plasticity silt, fine to coarse sand, fine to coarse gravel, subrounded cobbles, (possible alluvium).

Stiff sandy CLAY (CH); brown, damp, high plasticity, fine sand, (allluvium).

Trace fine to coarse subrounded gravel below ±4 feet.

Very dense GRAVEL and COBBLES, some silt and sand (GP-GM); brown and iron-stained, moist, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense GRAVEL, some clay and sand (GP-GC);

blue-grey, wet, medium plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium).

Drilling action suggests boulder from ±22.5 to 24.5 feet.

Very loose silty SAND (SM); grey, wet, low plasticity silt, fine sand, (alluvium).

Medium dense with scattered organics consisting of wood debris below ±27.5 feet.

Very dense GRAVEL, some silt and sand, scattered cobbles (GP-GM); grey, wet, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense clayey GRAVEL, some sand (GC); grey, wet, medium plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium).

Weak (R2) silty SANDSTONE; grey, fresh, fine sand, (Payne Cliffs Formation).

Weak (R2) MUDSTONE; light grey, fresh, (Payne Cliffs Formation).

BOTTOM OF BORING

1204.3 0.2

1202.0 2.5

1196.2 8.3

1184.5 20.0

1180.0 24.5

1175.0 29.5

1164.5 40.0

1162.5 42.0

1157.0 47.5

1154.4 50.1

SPT

N-Value

Moisture (%) Groundwater Log

Depth

Depth and

Comments

Core Recovery (%)

RQD (%)

0 50 100

Elev. Backfill/ Installations/

(ft)

Sample Number and Location

Soil / Rock Description

2241113

BORING LOG: BH- 2Project No.:

Surface Elevation:

Date of Boring: September 17, 2024

Medford RWRF Improvements

Jackson County, Oregon

BH- 2

1204.5 feet (Approx.)

Professional Geotechnical Services Foundation Engineering, Inc.

50/1st 5"

50/1st 2"

50/3"

50/1st 5"

50/1st 5"

50/3"

50/1st 2"

50/1st 1"

50/1st 5"

50/1st 2"

50/3"

50/1st 5"

50/1st 5"

50/3"

50/1st 2"

50/1st 1" chips

SS-3-1

SS-3-2

SS-3-3

SS-3-4

SS-3-5

SS-3-6

SS-3-7

SS-3-8

SS-3-9

SOD (±2 inches).

Very dense clayey GRAVEL, some sand, scattered cobbles (GC); brown, damp, medium plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded cobbles, (alluvium).

Very dense silty GRAVEL, some sand, scattered cobbles (GM); grey-brown and iron-stained, damp, low plasticity silt, fine to coarse sand, fine to coarse gravel, subrounded cobbles, (alluvium).

Very dense GRAVEL and COBBLES, some silt and sand (GP-GM); grey-brown, moist, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Drilling action suggests a boulder from ±12 to 14 feet.

Very dense clayey GRAVEL, some sand, scattered cobbles (GC); grey, moist, medium plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

BOTTOM OF BORING

1204.8 0.2

1200.0 5.0

1197.5 7.5

1180.0 25.0

1169.8 35.3

SPT

N-Value

Moisture (%) Groundwater Log

Depth

Depth and

Comments

Core Recovery (%)

RQD (%)

0 50 100

Elev. Backfill/ Installations/

(ft)

Sample Number and Location

Soil / Rock Description

2241113

BORING LOG: BH- 3Project No.:

Surface Elevation:

Date of Boring: September 18, 2024

Medford RWRF Improvements

Jackson County, Oregon

BH- 3

1205.0 feet (Approx.)

Professional Geotechnical Services Foundation Engineering, Inc.

50/5"

50/1st 5"

50/1st 5"

50/1st 3"

50/1st 2"

50/2"

50/1st 6"

50/1st 3"

50/5"

50/1st 5"

50/1st 5"

50/1st 3"

50/1st 2"

50/2"

50/1st 6"

50/1st 3" chips

SS-4-1

SS-4-2

SS-4-3

SS-4-4

SS-4-5

SS-4-6

SS-4-7

SS-4-8

SS-4-9

SS-4-10

SS-4-11

SOD (±1-inch).

Very dense silty CRUSHED ROCK (GR); brown, dry, low plasticity silt, ±1-inch minus angular rock, (fill).

Very dense silty GRAVEL, some sand and cobbles (GM);

brown, dry, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded cobbles, (possible alluvium).

Very stiff sandy CLAY, some gravel (CH); brown and iron-stained, damp, high plasticity, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium).

Cobbles at ±3.5 feet.

Very stiff sandy SILT (ML); brown and iron-stained, damp, low plasticity, fine sand, (alluvium).

Very dense sandy GRAVEL, some silt (GP-GM); brown, moist, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium).

Very dense GRAVEL and COBBLES, some silt and sand (GP-GM); grey, moist, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Drilling action suggests possible sand/silt lens from ±21 to 22 feet.

Very dense clayey GRAVEL, some sand, scattered cobbles (GC); dark grey, wet, medium plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very weak (R1) silty SANDSTONE; light grey, slightly weathered, fine sand, (Payne Cliffs Formation).

BOTTOM OF BORING

1204.9 0.1

1204.5 0.5

1203.0 2.0

1201.0 4.0

1198.5 6.5

1195.0 10.0

1171.5 33.5

1160.5 44.5

1159.8 45.3

SPT

N-Value

Moisture (%) Groundwater Log

Depth

Depth and

Comments

Core Recovery (%)

RQD (%)

0 50 100

Elev. Backfill/ Installations/

(ft)

Sample Number and Location

Soil / Rock Description

2241113

BORING LOG: BH- 4Project No.:

Surface Elevation:

Date of Boring: September 19, 2024

Medford RWRF Improvements

Jackson County, Oregon

BH- 4

1205.0 feet (Approx.)

Professional Geotechnical Services Foundation Engineering, Inc.

85/11"

50/3"

50/1st 3"

50/1st 5"

50/1st 4"

50/1st 2"

50/1st 3"

50/1st 4"

50/1st 3"

85/11"

50/3"

50/1st 3"

50/1st 5"

50/1st 4"

50/1st 2"

50/1st 3"

50/1st 4" chips

SS-5-1

SS-5-2

SS-5-3

SS-5-4

SS-5-5

SS-5-6

SS-5-7

SOD (±2 inches).

Very dense GRAVEL and COBBLES, some silt and sand (GP-GM); brown, dry, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very stiff sandy CLAY, some gravel, scattered cobbles (CH); brown, damp, high plasticity, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded cobbles, (alluvium).

Dense to very dense GRAVEL and COBBLES, some silt and sand (GP-GM); brown, moist, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Lost drilling fluid circulation (±250 gallons) between ±7.5 and 12.5 feet.

Scattered cobbles from ±15 to 20 feet.

BOTTOM OF BORING

1204.3 0.2

1200.0 4.5

1197.0 7.5

1179.3 25.2

SPT

N-Value

Moisture (%) Groundwater Log

Depth

Depth and

Comments

Core Recovery (%)

RQD (%)

0 50 100

Elev. Backfill/ Installations/

(ft)

Sample Number and Location

Soil / Rock Description

2241113

BORING LOG: BH- 5Project No.:

Surface Elevation:

Date of Boring: September 24, 2024

Medford RWRF Improvements

Jackson County, Oregon

BH- 5

1204.5 feet (Approx.)

Professional Geotechnical Services Foundation Engineering, Inc.

50/6"

50/4"

50/1st 2"

50/6"

50/4"

Capped with AC cold patch and gravel

Backfilled with bentonite chips

SS-6-1

SS-6-2

SS-6-3

SS-6-4

SS-6-5

SS-6-6

SS-6-7

ASPHALT CONCRETE (±3 inches).

Dense CRUSHED GRAVEL (GP); grey, moist, ±¾-inch minus subangular to subrounded gravel, (base rock).

Very dense clayey SAND, trace gravel, scattered cobbles (SC); brown, moist, medium to high plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Very dense GRAVEL and COBBLES, some silt and sand (GP-GM); brown and iron-stained, moist, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded to rounded cobbles, (alluvium).

Dense silty GRAVEL, some sand (GM); brown and iron-stained, wet, low plasticity silt, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium).

Very dense clayey GRAVEL, some sand, scattered cobbles (GC); grey, wet, medium to high plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, subrounded cobbles, (alluvium).

BOTTOM OF BORING

1205.8 0.3

1204.8 1.3

1202.5 3.5

1186.0 20.0

1181.0 25.0

1180.3 25.8

SPT

N-Value

Moisture (%) Groundwater Log

Depth

Depth and

Comments

Core Recovery (%)

RQD (%)

0 50 100

Elev. Backfill/ Installations/

(ft)

Sample Number and Location

Soil / Rock Description

2241113

BORING LOG: BH- 6Project No.:

Surface Elevation:

Date of Boring: September 25, 2024

Medford RWRF Improvements

Jackson County, Oregon

BH- 6

1206.0 feet (Approx.)

Professional Geotechnical Services Foundation Engineering, Inc.

60/7"

50/1st 5"

50/1st 5"

50/1st 2"

50/1st 6"

50/3"

60/7"

50/1st 5"

50/1st 5"

50/1st 2"

50/1st 6"

50/3" patch and gravel

Backfilled with bentonite chips

SS-7-1

SS-7-2

SS-7-3

SS-7-4

SS-7-5

SS-7-6

SS-7-7

ASPHALT CONCRETE (±3 inches).

Dense CRUSHED GRAVEL (GP); grey, moist, ±¾-inch minus subangular to subrounded gravel, (base rock).

Very dense clayey SAND, some gravel (SC); grey-brown, damp, high plasticity clay, fine to coarse sand, fine to coarse subrounded to rounded gravel, (alluvium).

Dense silty gravel lens from ±3.5 to 4 feet.

Very stiff sandy SILT (ML); brown and iron-stained, damp, low plasticity, fine sand,…